Human breast cancer often spreads to the lymph nodes of a patient, thereby requiring the removal of one or more of the linguinal or axillary lymph nodes. This type of lymph node removal as a component of breast cancer surgery is very common. After surgery involving lymph node removal, a large number of breast cancer patients experience a condition known as lymphedema. Lymphedema occurs as both an acute and chronic condition in which significant and persistent swelling associated with an abnormal accumulation of protein-rich fluid is experienced in the affected areas, such as the arms. This swelling can cause extreme pain in the arms and cosmetic issues, which affect the quality of life experienced by lymphedema sufferers.
Among the two million breast cancer survivors in the United States, it is conservatively estimated that 20-40% will develop chronic lymphedema within their lifetimes. The extensive nature of this disease makes the development of devices which monitor and treat lymphedema, a necessity, if the quality of life of its sufferers is to be improved. Lymphedema is most commonly treated by subjecting the patient's arms to pressure cuff treatment. The pressure cuff device essentially wrings the protein-rich fluid from the patient's arms, thereby reducing swelling. Another form of treatment is for the patient to wear body-constricting garments such as arm tubes constructed from tight-weave material which constricts the arm, thereby maintaining the reduced volume and shape of the arm.
The types of devices which are used in medical facilities to monitor and measure lymphedema include that disclosed in French Patent No. FR2682279 by Cauzot et al. The Cauzot patent describes a device which uses a sheath to fit over a patient's limb, the sheath is then filled with a compressible or incompressible fluid. A volume computer measures the increase in volume of a patient's arm due to swelling. Further, this device is used as a pressure cuff in pressure therapy. A drawback to the Cauzot device is that it is required to be hooked to a nearby fluid source or else a fluid source must be transported along with the device, thereby limiting its transportability and location of use.
U.S. Pat. No. 5,948,977 by Siconolfi describes a displacement volumometer for measuring a whole body or a single limb. A person places his entire body or a single limb within a large air bag and the bag is compressed to two positions and compared against a constant air pressure when the bag is empty and fully inflated. The person's body or limb volume is then calculated based upon the changes in volume according to Boyle's law. The large size of the air bag associated with this device makes it impractical from a portability standpoint as well.
The “Mercury Plethysmograph” Publication describes estimating changes in body or limb volume by using an apparatus comprised of an inflated cuff coupled around a limb that is coupled to air flow and pressure transducers. The purpose of the apparatus is to measure fluid perfusion into a limb. While transportable, this device requires some significant time spent in coupling and positioning the cuff around the limb, inflating it, and then allowing enough time for an accurate reading to be taken. Also, the inflatable cuff is more prone to wear and puncture, thereby limiting its operational life.
A need therefore exists for a portable and durable apparatus for accurately measuring lymphedema in patients. Further, it would be desirable for such a device to quickly take lymphedema measurements with as little patient interference as possible.
The foregoing discussion reflects the state of the art which the inventor is aware, and is tendered with a view toward discharging the inventor's acknowledged duty of candor in disclosing information which may be pertinent with regards to the patentability of the present invention. It is respectfully stipulated, however, that the disclosed information does not teach or render obvious, singly or when considered in combination, the inventor's claimed invention.